Reader question: I’m getting really confused by all this talk of “alkaline diet”, are there really health benefits are is this just another fad?


I’m getting really confused by all this talk of “alkaline diet”, are there really health benefits are is this just another fad?

-Baffled in Battersea


Of course you’re confused! The entire business model of the nutritional-media-industrial complex relies on your confusion to sustain it. Since they have almost nothing of value to offer, keeping you confused is the only way to keep you clicking and spending.


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Reader question: What is your opinion on nootropic supplements, such as Alpha Brain?


What is your opinion on nootropic supplements, such as Alpha Brain? Studies have shown that it can significantly boost energy levels, mental speed, memory, creativity and focus. Do you think taking something like this could be risky? Is it worth it?

-Clouded in Clapham


I’ll keep this one short. I wouldn’t take any such supplements. The “studies” in support of the supplement that you’re asking about were funded by the company that sells the supplement. Studies like that should be immediately disregarded.

I’m not aware of any compelling evidence in favor of “cognitive enhancer” supplements. And that’s not because there is some vast conspiracy among the scientific community to keep potentially helpful things from the public. If these supplements worked, there would be proper studies supporting them.


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Reader question: What is your opinion on “healthy” meal replacement drinks such as Huel? It’s vegan, high in fibre and has a good balance of macro and micro nutrients. But it’s also a processed food. Can it play a role in a healthy diet?


What is your opinion on “healthy” meal replacement drinks such as Huel? It’s vegan, high in fibre and has a good balance of macro and micro nutrients. But it’s also a processed food. Can it play a role in a healthy diet?

-Curious in Coulsdon


I wouldn’t get too caught up in whether something is ‘processed’ or not.

(See previous reader question: Is processed vs. unprocessed really the right distinction?)


To answer your question, I think we need to start with a different one:

Why would you eat a meal replacement instead of ‘normal’ food?


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Intermittent fasting could help tackle diabetes – here’s the science


A similar version of this article appeared on


Intermittent fasting is currently all the rage. But don’t be fooled: it’s much more than just the latest fad. Recent studies of this kind of fasting – with restricted eating part of the time, but not all of the time – have produced a number of successes, but the latest involving diabetes might be the most impressive yet. (more…)

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Reader question: Is processed vs. unprocessed really the right distinction?


Two related questions from different readers:

So processed foods with carbs like rice and pasta and bread are problematic. What about potatoes? They’re vegetables. Do potatoes have fiber?

– Puzzled in Plaistow

In your book you talk about “processed food” a lot, highlighting that processes which remove fiber or add sugar are particularly harmful. Unless we start eating only raw vegetables, isn’t almost everything we eat processed? Isn’t cooking a process? Boiled or roast carrots are sweeter than raw ones… and fried (caramelised?) onions are sweet while raw ones aren’t.  Does cooking reduce fiber or chemically increase the fructose content in food?

– Unsure in Upney



These are good questions. The processed vs. unprocessed distinction is generally a good one, but it is oversimplified and indirect. (more…)

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Reader question: Is alternating between high- and low-calorie days a good idea?


If I eat 21,000 calories a week evenly at 3,000 per day, would I weigh the same as if I alternated between good days (1,500 calories) and bad days (4,500 calories)?

– Wondering in Wimbledon


Hmm … This seems like an experiment that must have been done, but I can’t find evidence of it anywhere.

I’m guessing here, but I think that in this specific example you would be worse off on the alternating plan. Assuming you are an average-sized person, 4,500 calories is quite a lot and is likely to stress your metabolic pathways and lead to inflammation, while 1,500 calories probably isn’t few enough to elicit any of the benefits of intermittent fasting. (more…)

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Reader question: What’s the deal with superfoods?


Hello, I have an overweight friend who follows a particular program where she drinks a shake for her meal. The shake she is drinking has about 70 different superfoods including goji berry, yacon root, chlorella, and so forth. I tried to read some references to understand the evidence for some superfoods, but it was a bit difficult to interpret. I would greatly appreciate if you could expand on this topic.

– Worried in Surrey


I think it’s helpful to start with the following two statements:

(1) If your diet is a reasonable mix of mostly unprocessed foods, the specifics of what you are eating do not matter.

(2) If your diet is not a reasonable mix of mostly unprocessed foods, you should change your diet.

Let’s consider superfoods in the context of each of these statements, starting with (1). (more…)

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Is brain inflammation the cause of obesity?


A similar version of this article appeared on


A new study has found something remarkable: the activation of a particular type of immune cell in the brain can, on its own, lead to obesity in mice. This striking result provides the strongest demonstration yet that brain inflammation may be a cause, rather than a consequence, of obesity. It also provides promising leads for new anti-obesity therapies.

The evidence linking brain inflammation to obesity has been building for some time. Consistent overeating causes stress and damage to cells in the body and brain. This damage results in a response from the immune system that has a wide range of effects.

Some of these effects help to reduce the problems caused by overeating, but others seem to make things worse. For example, in the hypothalamus – the part of the brain that controls, among other things, eating and activity – inflammation causes problems such as leptin resistance that interfere with the regulation of body weight.

Leptin is a hormone that is released by fat cells and provides the brain with information about the amount of energy stored as body fat. Normally, neurons in the hypothalamus that are sensitive to leptin will use this information to regulate eating and activity as needed to maintain body fat within some desired range.

In obesity, however, these neurons become insensitive to leptin. As a result, they no longer trigger the decrease in hunger and increase in energy expenditure that are necessary to lose excess weight. This is why the vast majority of attempts by obese people to lose weight fail – inflammation causes the brain to fight against it every step of the way.

So brain inflammation clearly plays an important role in sustaining obesity. But could it also be one of the primary causes of obesity in the first place? The onset of brain inflammation coincides with the other changes that take place in the body and brain as a result of overeating and weight gain. But whether brain inflammation actually causes the development of obesity is not yet clear. The results of the new study, however, demonstrate that the activation of a particular type of brain immune cell, microglia, initiates a cascade of events that do indeed lead directly to obesity.

In the study, researchers at the University of California, San Francisco and the University of Washington performed experiments on mice. They found that altering the activity of microglia in the hypothalamus allowed them to control the body weight of the mice independent of diet.

The researchers began by testing the effects of reducing either the number of microglia or their level of activity. They found that both manipulations cut the weight gain that resulted from putting the mice on high-fat diet in half.

They then tested the effects of increasing the activity of microglia. They found that this manipulation caused obesity even in mice that were on a normal diet. This latter result is particularly surprising. The fact that obesity can be induced through microglia – rather than directly through neurons themselves – is an indication of how strongly the brain’s supporting cells can exert control over its primary functions.

So artificial brain inflammation can cause obesity in mice. Of course, that doesn’t mean that natural, diet-induced brain inflammation does cause obesity in humans. But these new results suggest that this idea is worth taking seriously, particularly given that fact that potential solutions to the obesity crisis are in short supply.

This new study alone has already identified several possible targets for anti-obesity drugs. Intriguingly, one of the same drugs that was used in the study to decrease activity in microglia is also being tested in human cancer trials, so initial indications of its effects on body weight should be available soon. But either way, a deeper understanding of the role of brain inflammation will help to clarify the causes of obesity. And hopefully prompt ideas about how it can be avoided in the first place.

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The ultimate eating challenge: long-haul travel


I always say that every meal is a gift: an opportunity for pleasure that I refuse to squander.

Now, ideally, I’d like everything I eat to be both healthy and tasty. But I recognize that there are certain situations in which I may have to, or even want to, eat something that isn’t necessarily both of those things.

Often I’ll eat something unhealthy but tasty just for the pleasure, and less often I’ll eat something healthy but bland if I have no other choice (e.g. at a work function). So unhealthy or bland I can handle, but unhealthy and bland is just not something I’m OK with. But that is, of course, exactly what is offered on an airplane (at least in economy class; I’ve never had the opportunity to test the food in business).

Fortunately, I learned a long time ago that, with a little advance preparation, eating healthy and tasty food on an airplane is really no problem. So I thought I’d describe what I ate on a recent flight from London to Bangkok to illustrate exactly how I do it.

The flight left London around noon and lasted about 11 hours, so I needed to eat both lunch and dinner, as well as a few snacks. I stopped at Borough Market the day before the flight for supplies (Yes, I actually thought about this the day before the flight. Healthy and tasty on an airplane doesn’t just happen!). On the morning of the flight, I spent about 30 minutes preparing the following:


Tomatoes, Burrata, Wild Garlic Pesto, Olives



Tuna, Green Beans, Garlic (and olive oil for cooking)


Coffee, Dark chocolate, Almond biscuits, Fruit Salad


Here’s what it all looked like ready to go:

(all x2 because there were two of us)


I also always ask for the fruit/vegatarian/vegan meals just in case of emergency. These are unlikely to be very tasty, but they are at least usually healthy:


The final verdict

I’ve done this many times before, so it was no surprise that it was a great success. And seeing the dire offerings that my neighbors on the flight were forced to endure left me feeling quite smug indeed.

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Finding the Christmas sweet spot: indulging without overindulging


I love everything about Christmas: the music, the movies, the decorations, and, of course, the food. But it’s a dangerous time with many unhealthy temptations that I’m not normally faced with and, in years past, I’ve struggled to not overdo it.

This year, I am determined to find the sweet spot and indulge without overindulging. Like most people, I’m pretty unlikely to end up in the sweet spot by chance. If I just passively go through the Christmas holidays without a plan, I can pretty much guarantee that I’ll end up on the side of overindulgence. However, I’m confident that with a bit of strategizing and deliberate action, I’ll be able to moderate my indulgence, but – and this is the critical part – without feeling like I’m depriving myself.

In addition to the general risk of Christmas excess, I’m up against some particular challenges:

First of all, my family does a few (OK, quite a few) traditional homemade Christmas treats that I love to the point where not eating them is not an option. We make a lot of different Christmas cookies, peppermint marshmallows, gingerbread pancakes, a chocolate yule log – you get the picture. I’m not going to forgo any of these things, so I’ll have to find ways to cut back on the excess elsewhere.

Second of all, we are also hosting visitors from out of town for the week of Christmas, and I am not going to allow my quest for the sweet spot to be an imposition on them. We are going to eat wherever and whenever they want to.

And, finally, there will be an unavoidable drop in my activity level. I am normally highly active: I walk about 5 miles a day (most of which is my commute to work) and exercise intensely about 3 times per week, usually either squash or basketball. The walking is likely to be cut back significantly during the Christmas week as I won’t be going to work, and the intense exercise will be eliminated completely. (A good strategy might be to try to sneak in a few early morning runs or something like that, but, unfortunately, I hate running. I could force myself to do it, but that would decrease my enjoyment of the whole Christmas week. I think I’ll be better off just trying to be strategic about my overindulgence and sneaking in some walking whenever I can).

Well, here we go …


December 22

The plan

Our visitors arrive this afternoon and we’re planning to have dinner with them at a burger place. I don’t feel the need to do anything out of the ordinary before they arrive: I’m just going to eat my normal breakfast, walk to work (~3 miles), eat my normal lunch, and eat a light afternoon snack. The burger place that we are going to for dinner is pretty good (BRGR.CO in SoHo), so I’ll want to actually have a burger and fries, but I plan to compensate somewhat for the low dietary quality of the meal by eating a relatively small amount.

Reality check

Everything went according to plan in the morning and afternoon. I had a very tasty and reasonably-sized burger for dinner along with a half portion of fries, a beer, and a side of spinach. I can see that one of the great challenges over the week is going to be keeping up my fiber intake. Christmas is no excuse for starving one’s gut bacteria! As I general rule, I’m going to substitute fiber for starch (i.e. non-potatoes for potatoes) whenever possible. Also, the end of the day brought an activity bonus: I walked home from dinner (~3 miles). So far, so good, but the challenges begin in earnest tomorrow.


December 23

The plan

Today we are making a full-day sightseeing excursion to Leeds Castle. I’m going to eat a normal breakfast at home and then walk to Victoria station (~3 miles) to catch the train to the castle. The options for lunch at the castle are likely to be dire and I plan to use that to my advantage: since I know that I won’t get much enjoyment from eating anything at the castle, I’m just going to pick something relatively harmless and eat very little of it. That will leave me well-positioned for an afternoon snack and dinner. There is not yet a fixed plan for dinner as we are unsure about when we will return from the castle …

Reality check

Breakfast and the walk to Victoria went according to plan. The visit to the castle involved a fair amount of walking, which was a nice bonus. There was a pop-up Christmas market at the castle and, thus, the food options were more enticing than I’d imagined. But there wasn’t anything that I was that excited about, so I stuck to the original plan and had a half portion of a chickpea curry. I had two of our homemade Christmas cookies for an afternoon snack. We arrived home in time for a proper dinner and made a booking at a Georgian restaurant (Little Georgia in Angel). This was a real winner: our guests were treated to something slightly exotic but still accessible, while I enjoyed all manner of tasty vegetables. And I walked home from the restaurant (~3 miles). I had a celebratory rum before bed. Right now, confidence is high.


December 24

The plan

Today we are going to a matinee showing of Rogue One and then eating lunch at a typical dim sum restaurant in Chinatown. Our afternoon plans are up in the air, but we will cook dinner in the evening at home. I’m going to eat a normal breakfast at home and then do a bit of shopping and walk to the movie (~3 miles). I plan to eat a normal amount at lunch, with the hope of sneaking in some greens with my dim sum. Dinner will be pork belly, bacon, and potatoes, with wine, cheese and sweets. I know that I’m going to enjoy the food at dinner a lot and I don’t want to miss out on any of it, but I do plan to limit myself to one large serving of everything.

Reality check

Breakfast, shopping, and the walk to the movies went according to plan. Lunch was tasty and I didn’t overdo it too badly. I did get my greens, and also some very tasty black sesame dumplings for dessert. I also had a few of our homemade marshmallows for an afternoon snack. Dinner also went according to plan: I had enough of everything to really enjoy the meal, but not so much as to feel like I overdid it. So heading into Christmas day, I’m right where I want to be: I’ve enjoyed myself so far without really overdoing it, and I’ve kept my activity level relatively high. But Christmas day is going to be a different story.


December 25

The plan

Today I am not planning to leave the house. My eating will be ‘limited’ to two meals and an afternoon snack. The first meal will be a brunch full of various unhealthy, traditional foods that I love. The afternoon snack will be some of our homemade cookies. Dinner will be beef with a number of different sides – some healthy, some not – as well as wine, cheese, and sweets. My general plan is again to limit myself to one large serving of everything.

Reality check

I did indeed manage to avoid leaving the house. I handled breakfast well: it was certainly much more food (and much more sugar and starch) than I would normally eat, but I really enjoyed it. I had three cookies for an afternoon snack. I pigged out at dinner, but, again, not too badly. I did go back for seconds of the final chocolate yule log, but, hey, it’s Christmas. Viewed in a vacuum, today was a very unhealthy day: I overate unhealthy food and did absolutely nothing active. It’s the kind of day that I would normally feel badly at the end of. But when I consider it together with the preceding days as part of my larger Christmas plan for moderate overindulgence, I’m left with just the enjoyment and no regrets. My plan is working. And tomorrow is already boxing day: I’m over the hump.


December 26

The plan

Today we are going to meet our visitors for lunch somewhere near their hotel, go to an exhibition in the afternoon, and then go out for dinner, hopefully for Lebanese (assuming we can find something that is open on Boxing Day). I plan to eat an almost-normal breakfast (there are a few leftover sugars and starches from the Christmas breakfast that I plan to finish off) and then walk to lunch (~3 miles). My lunch strategy will depend on where we eat. I’m planning a small afternoon snack. And I’ll eat Lebanese as I always do: heavy on the veg mezze.

Reality check

Breakfast and the walk went according to plan. We ate lunch at a not-so-great restaurant (no reason to name and shame). I knew I wouldn’t really enjoy the food there, so I took the opportunity to pick at a salad and offset a bit of the previous day’s overindulgence. I had a few marshmallows for an afternoon snack. I ate a bit more than I intended at dinner (Al Masar, our local Lebanese), since there were so many different dishes on the table to try, but I didn’t overdo it too badly. Overall, it was a good follow-up day for Christmas. Only one more day before things get back to normal.


December 27

The plan

Today we are planning another full-day outing to Bletchley Park. I plan to have a normal breakfast and walk to Euston station (~ 3 miles). As with the castle, I assume the lunch options at Bletchley will be dire, so I plan to eat very little. We have a booking for afternoon tea back in London and we have not yet made any plans for dinner. Inasmuch as afternoon tea is going to be largish meal, then this is going to be very awkward: I love the traditional sweets that come with tea, but if I eat a lot of them I certainly won’t want to eat dinner afterward. I’m not sure how this is going to play out …

Reality check

Breakfast and the walk went according to plan. Actually, we stopped for a hot chocolate at Hotel Chocolat on the walk to the station, which was unintended, but very, very good. Fortune smiled upon us at Bletchley: they had an afternoon tea of their own served in their mansion, so we opted for that around lunch time and canceled the tea booking back in London. I ate quite a few of the sweets and left the sandwiches. We went for fish and chips for dinner. I had a half an order of cod and chips with the usual sauces, a few grilled sardines, and a beer. And a chacha at home before bed.


The final reckoning

I think that I succeeded in finding the sweet spot, and it wasn’t all that hard in the end. I really didn’t have to do anything that felt forced: it was enough to just keep it in mind as an explicit goal to guide my decisions throughout the week. But there is no question that having visitors was a big help. Because we had so many activities planned, it gave me a lot of excuses to get some walking in. It also gave me an excuse to forgo enjoyment at certain meals without feeling like I was depriving myself. Next year, if we don’t have visitors, it will be harder. But I’ll be ready.

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